SDAA210 November   2025 LM5125-Q1 , LM51251A-Q1 , LM5125A-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Application Implementation
  6. 3Design Considerations
  7. 4Test Results
    1. 4.1 Efficiency Measurements
    2. 4.2 Device Features
      1. 4.2.1 Soft-Start (SS)
      2. 4.2.2 Over-Voltage Protection (OVP)
      3. 4.2.3 Second phase enable (EN2)
      4. 4.2.4 Bypass mode
    3. 4.3 Load Transient
    4. 4.4 Line Transient
    5. 4.5 Temperature Measurements
    6. 4.6 Bode Plot
  8. 5Summary
  9. 6References

4.2.4 Bypass mode

Bypass mode is triggered whenever the input voltage rises above the output voltage. Interesting to note here, as shown in Figure 4-5, is that as soon as this happens the device stops switching (waveform in blue). The output follows the input voltage (yellow and green, respectively), minus the diode voltage drop.

Bypass mode behavior Figure 4-5 Bypass mode behavior